Among cellulosic materials wood is a very useful material which for its manufacture does not require large quantities of energy since it is formed in nature and since its processing is relatively simple. Wood possesses many advantages from the point of view of its use as a raw material and is thus easily machined, has a relatively high strength and good heat insulating properties, it is resistant to chemical attack etc. Wood is mostly used as a construction material for the manufacture of furniture, for domestic interior decoration and, of course, it is a highly important raw material for the building industry.
It is known that wood can decompose due to atmospheric conditions, uptake of water etc. and it is of importance to protect wood products by impregnating and/or surface treatment. Impregnation is a process whereby the pore system of the wood permanently or temporarily are filled with active substances in gas or liquid form. The surface treatment consists in the prevention of different types of surface coatings, such as paint, lacquer or the like.
A principal problem in using wood as a construction material resides in the fact that the wood by variations in moisture content is subjected to dimensional changes with disadvantageous results. Thus, fissures or cracks can form enabling transportation of moisture and spores resulting in for example attack by microorganisms. The dimensional instability can further result in damages to paint, interior decoration etc. Several attempts have been made to reduce the dimensional variations of wood due to variations in moisture content but so far with little or no success. Most of the known methods for treating wood and wood products have for a main purpose to eliminate the growth of microorganisms by the introduction of fungicides. Thus, the prior art methods have not for a main purpose to reduce or eliminate dimensional changes.